TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC I47 



TEMPERATURE VARIATIONS AND SUN SPOTS 



Only a short time after the discovery of sun spots by the EngHsh- 

 man Harriot on December lo, 1610, the German Joh. Fabricius on 

 March 9, 161 1, the Italian Galileo, and the German Jesuit Scheiner, 

 the Jesuit Father Riccioli in the year 165 1 announced that with a 

 decrease of the sun spots the temperature of the earth increases and 

 with an increase of them it diminishes. Later on many investiga- 

 tors occupied themselves with this matter of whom some found the 

 relation to be inverse, the temperature rising with increasing num- 

 bers of sun spots. Among the latter may be mentioned William 

 Herschel (1801), who came to this conclusion through studies of 

 the wheat prices in Windsor. 



The Bavarian astronomer Gruithuisen came to the same conclu- 

 sion in 1826, but he also made the following peculiar announcement 

 which was based on thirty-six years' experience in Munich. " Settled 

 fine weather occurs on the earth, when on the sun the variable 

 weather (that is, sun spot formation) ceases. Great spots call forth 

 on the earth variable weather differing greatly in different localities. 

 The more scattered the spots occur, the less does the temperature of 

 the earth's atmosphere rise since only spot groups or great spots 

 send forth more heat." (See Mielke, 1913, p. i). 



Alfred Gautier (1844) of Geneva, like many others, arrived at 

 the conclusion that years of many sun spots were colder than those 

 with few. He also made the valuable discovery that a periodicity 

 occurs in the spots and he determined the period as about ten years, 

 that is, five years after each sun spot maximum there follows a mini- 

 mum.* This period which had been observed since 1825 by Schwabe, 

 was soon more accurately and thoroughly determined by Rudolf 

 Wolf in Zurich, who found it to be eleven and one-ninth years. 



We can mention here only a few of the investigations in this 

 field, and must refer to the historic treatises on the subject, as 

 for example those of von Hahn (1877), Fritz (1878-1893), S. 

 Gunther (1899), Arrhenius (1903), Hann (1908), Wallen (1910), 

 and Mielke (1913). 



After the assembly of a great quantity of observational material, 

 taken over the period of time from 1744 (or even 1719 at Berlin) 

 to 185 1 at Milan, Vienna, Kremsmunster, Hohenpeissenberg, Prague, 



^Already in the year 1776 the Dane Ilorrebow in his day book of unpub- 

 lished observations indicated the probability that one would find a period in 

 the variations of the sun spots and that this might also be of importance to 

 the planets which are carried on by the sun and lighted by it. 



